EPA conducted a Preliminary Assessment/Site Investigation as part of a Formerly Used Defense Site (FUDS) review of the former Nike Battery #87 property. A background groundwater sample was taken in October 2004 near the Nike Battery #87 property where three residences were located. Trichloroethylene (TCE) was detected in one residential drinking water well at 76 parts per billion (ppb) and another nearby residential drinking water well at 150 ppb. Both concentrations exceeded the National Primary Drinking Water Standards for TCE. The maximum contaminant level for TCE is 5 ppb.
During August 2005, EPA conducted a more thorough evaluation of the area, including sampling other neighboring residential drinking water wells. A third drinking water well was found to contain TCE at 53.9 ppb.
On September 19, 2005, EPA conducted an emergency response action to install activated carbon (AC) filtration drinking water treatment systems at the three residences where TCE exceeded the MCL. Each system consists of two AC filter units that are point of entry systems, i.e., each receives water directly from the well and treats the water priort to distribution inside the home.
As result of taking water samples from the treatment systems in October 2007, it was discovered that an AC filter unit at one of the treatment systems had become saturated and resulted in filter breakthrough. In order to ensure that all three treatmetn systems were working as designed, in March 2008, regular maintenance that included replacing the AC filter unit was performed. After analysis of the potential lifespan of a filter unit was conducted, the decision to replace all filter units every 13-18 months was made.
The next scheduled regular maintenance was to occur in June 2009, but due to budget and contractor scheduling issues, regular maintenance on the three treatment systems was performed on April 21, 2009.
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The next steps for this site is to transition over the assessment work to the local health department, the treatment systems will be turned over to the care and maintenance of the residents, and the State of Washington Department of Ecology has agreed to provide one final filter change for the residents at the next scheduled maintenance period.
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